Mechanical cam phasing systems and methods

Abstract

Systems and methods for varying a rotational relationship between a cam shaft and a crank shaft on an internal combustion engine (i.e., cam phasing) are provided. In particular, systems and methods are provided that facilitates a rotary position of a first component to be accurately controlled with a mechanism causing a second component, which can be coupled to the cam shaft or crank shaft, to follow the rotary position of the first component.

We claim: 
     
       1. A cam phasing system comprising:
 a sprocket hub including a gear and a sprocket sleeve received within the sprocket hub; 
 a cradle rotor at least partially received within the sprocket hub and configured to rotate relative to the sprocket hub; 
 a plurality of locking assemblies arranged circumferentially around and radially between the sprocket sleeve and the cradle rotor; and 
 a spider rotor at least partially received within the sprocket hub and configured to rotate to a known rotary position relative to the sprocket hub in response to an input displacement applied thereto; 
 whereby rotation of the spider rotor in a desired direction to the known rotary position unlocks the plurality of locking assemblies, which, in turn, allows the cradle rotor to rotate relative to the sprocket hub and rotationally follow the spider rotor in the desired direction to the known rotary position. 
 
     
     
       2. The cam phasing system of  claim 1 , wherein the sprocket sleeve is fabricated from a material with a greater hardness than the sprocket hub. 
     
     
       3. The cam phasing system of  claim 1 , wherein the plurality of locking assemblies each include a first locking feature and a second locking feature. 
     
     
       4. The cam phasing system of  claim 3 , wherein rotation of the spider rotor in the desired direction displaces one of the first locking features and the second locking features to an unlocked position and one of the first locking features and the second locking features not displaced by the spider rotor remain in a locked position. 
     
     
       5. The cam phasing system of  claim 1 , further comprising a helix rod coupled to the spider rotor. 
     
     
       6. The cam phasing system of  claim 5 , wherein the helix rod includes a plurality of splines defining a helical portion configured to be received within and interact with a plurality of helical features in the spider rotor, and wherein the interaction between the helical portion of the plurality of splines and the plurality of helical features enable the rotation of the spider rotor in the desired direction to the known rotary position in response to the input displacement. 
     
     
       7. A cam phasing system comprising:
 a sprocket hub; 
 a cradle rotor including a central hub and a cradle sleeve received around the central hub; 
 a plurality of locking assemblies arranged circumferentially around and radially between the cradle sleeve and the sprocket hub; and 
 a spider rotor at least partially received within the sprocket hub and configured to rotate to a known rotary position relative to the sprocket hub in response to an input displacement applied thereto; 
 whereby rotation of the spider rotor in a desired direction to the known rotary position unlocks the plurality of locking assemblies, which, in turn, allows the cradle rotor to rotate relative to the sprocket hub and rotationally follow the spider rotor in the desired direction to the known rotary position. 
 
     
     
       8. The cam phasing system of  claim 7 , wherein the central hub includes at least one tab protruding radially outwardly therefrom, and the cradle sleeve includes at least one slot radially recessed into an inner surface thereof. 
     
     
       9. The cam phasing system of  claim 8 , wherein the at least one tab is dimensioned to be received within the at least one slot to rotationally interlock the central hub and the cradle sleeve. 
     
     
       10. The cam phasing system of  claim 7 , wherein the cradle sleeve is fabricated from a material with a greater hardness than the cradle rotor. 
     
     
       11. The cam phasing system of  claim 7 , wherein the plurality of locking assemblies each include a first locking feature and a second locking feature. 
     
     
       12. The cam phasing system of  claim 11 , wherein rotation of the spider rotor in the desired direction displaces one of the first locking features and the second locking features to an unlocked position and one of the first locking features and the second locking features not displaced by the spider rotor remain in a locked position. 
     
     
       13. The cam phasing system of  claim 7 , further comprising a helix rod coupled to the spider rotor. 
     
     
       14. The cam phasing system of  claim 13 , wherein the helix rod includes a plurality of splines defining a helical portion configured to be received within and interact with a plurality of helical features in the spider rotor, and wherein the interaction between the helical portion of the plurality of splines and the plurality of helical features enable the rotation of the spider rotor in the desired direction to the known rotary position in response to the input displacement. 
     
     
       15. A cam phasing system comprising:
 a sprocket hub including an inner surface; 
 a cradle rotor including a central hub and at least partially received within the sprocket hub; 
 a sleeve at least partially received within the sprocket hub and arranged radially between the inner surface of the sprocket hub and the central hub of the cradle rotor; 
 a plurality of locking assemblies circumferentially spaced and in engagement with the sleeve; and 
 a spider rotor at least partially received within the sprocket hub and configured to rotate to a known rotary position relative to the sprocket hub in response to an input displacement applied thereto; 
 whereby rotation of the spider rotor in a desired direction to the known rotary position unlocks the plurality of locking assemblies, which, in turn, allows the cradle rotor to rotate relative to the sprocket hub and rotationally follow the spider rotor in the desired direction to the known rotary position. 
 
     
     
       16. The cam phasing system of  claim 15 , wherein the sleeve is in engagement with the inner surface of the sprocket hub. 
     
     
       17. The cam phasing system of  claim 15 , wherein the sleeve is in engagement with the central hub. 
     
     
       18. The cam phasing system of  claim 15 , wherein the central hub includes at least one tab protruding radially outwardly therefrom, and the sleeve includes at least one slot radially recessed into a sleeve inner surface thereof. 
     
     
       19. The cam phasing system of  claim 18 , wherein the at least one tab is dimensioned to be received within the at least one slot to rotationally interlock the cradle rotor and the sleeve. 
     
     
       20. The cam phasing system of  claim 15 , further comprising a helix rod coupled to the spider rotor, wherein the helix rod includes a plurality of splines defining a helical portion configured to be received within and interact with a plurality of helical features in the spider rotor, and wherein the interaction between the helical portion of the plurality of splines and the plurality of helical features enable the rotation of the spider rotor in the desired direction to the known rotary position in response to the input displacement.